Speech Levels in Open Offices

Speech Levels in Open Offices

National Research National Research Council CanadaCouncil CanadaNational Research National Research Council CanadaCouncil Canada

Conseil nationalConseil nationalde recherches Canadade recherches CanadaConseil nationalConseil nationalde recherches Canadade recherches Canada

CanadaCanada

Alf Warnock & W.T. ChuAlf Warnock & W.T. ChuIndoor Environment Program, AcousticsIndoor Environment Program, Acoustics

Institute for Research in ConstructionInstitute for Research in Construction

National Research CouncilNational Research Council

Ottawa, OntarioOttawa, Ontario

Alf Warnock & W.T. ChuAlf Warnock & W.T. ChuIndoor Environment Program, AcousticsIndoor Environment Program, Acoustics

Institute for Research in ConstructionInstitute for Research in Construction

National Research CouncilNational Research Council

Ottawa, OntarioOttawa, Ontario

ASA December 2001ASA December 2001

Project: Team style open offices

Can some Can some degree of degree of speech privacy speech privacy be attained? be attained?

Need typical Need typical levels to make levels to make calculationscalculations

A B

C D


Team-style areas - real


Previous Work

Pearsons, Bennet & FidellPearsons, Bennet & Fidell– Different voice efforts measured but none in Different voice efforts measured but none in

open officeopen office

McKendreeMcKendree– Anechoic roomAnechoic room

No information on speech levels No information on speech levels measured in open officesmeasured in open offices


Recording Voice Levels


Sites and subjects

Nine offices - mix of team- and Nine offices - mix of team- and cubicle-stylecubicle-style

118 subjects, 53 male, 65 female118 subjects, 53 male, 65 female Also measured attenuations Also measured attenuations

between work stationsbetween work stations


Analysis

30 second segments with no 30 second segments with no prolonged silences.prolonged silences.

1/16 second integration time - 1/16 second integration time - 480 spectra480 spectra

Levels corrected to distance of Levels corrected to distance of 0.9 m by measurements in an 0.9 m by measurements in an anechoic chamberanechoic chamber


Attenuation


Result for one subject

0

10

20

30

40

50

60

70

16

0

20

0

25

0

31

5

40

0

50

0

63

0

80

0

10

00

12

50

16

00

20

00

25

00

31

50

40

00

50

00

63

00

80

00

Frequency, Hz

SP

L, d

B

LeqL90L50L10L1

L90L90

L50L50 LeqLeq

L10L10

L1L1


Average for each office - Males

20

25

30

35

40

45

50

55

250 500 1k 2k 4k 8k

Frequency, Hz

Ave

rag

e S

pe

ech

Le

vel,

dB

S1

S2

S3

S4

S5

S6

S7

S8

S9


Grand Average - Males

20

25

30

35

40

45

50

55

250 500 1k 2k 4k 8k

Frequency, Hz

Ave

rage

Spe

ech

Le

vel,

dB

NRC, Male

51.0 ± 3 dBA 51.0 ± 3 dBA


Grand Average - Females

20

25

30

35

40

45

50

55

250 500 1k 2k 4k 8k

Frequency, Hz

Ave

rag

e S

pee

ch L

eve

l, dB

NRC, Female

49.7 ± 3.8 dBA 49.7 ± 3.8 dBA


20

25

30

35

40

45

50

55

60

250 500 1k 2k 4k 8k

Frequency, Hz

Ave

rage

Sp

eec

h L

eve

l, d

B

ANSI S3.5 1997, 59.2 dBA

ASTM E1130, 57.5 dBA

Pearsons, M&F, 55.9 dBA

McKendree, M&F, 57.4 dBA

NRC, M&F, 50.3 dBA

Voice Spectra


Casual vs. Open Office

25

30

35

40

45

50

55

60

250 500 1k 2k 4k 8k

Frequency, Hz

Ave

rag

e S

pe

ech

Le

vel,

dB

15

20

25

30

35

40

45

50

NRC, F, 49.7 dBAPearsons casual, F, 49.3 dBANRC, M, 51.0 dBAPearsons casual, M, 51.3 dBA

Males

Females


Average Voice Levels

Leq

0

5

10

15

20

39 41 43 45 47 49 51 53 55 57 59 61 63

Level, dB(A)

Num

be

r of

Su

bje

cts

MaleFemale


0

20

40

60

80

100

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

SII

Pe

rcen

t

NRC voice

ASTM voice

SII and voice level

Measured attenuations Measured attenuations Same noise spectrum Same noise spectrum Different voice levelsDifferent voice levels

Documents

Speech Levels in Open Offices